Control of transcriptional integrity by Integrator and PP2A

Objective: The overall goals of this application are understanding the molecular basis of RNA Polymerase II (RNAPII) pausing and pause-release and determining how disease-associated mutations in the PP2A phosphatase reverse the pausing balance to promote transcriptional elongation. Proposed research: The mammalian RNAPII transcription cycle is regulated by cyclin-dependent kinases (CDKs) that target the catalytic core of RNAPII and many of its co-factors. We recently identified Int-PP2A, a module of the RNAPII-associated Integrator complex that recruits the PP2A phosphatase to active genes to oppose CDK9 activity. We demonstrated that Int-PP2A targets Ser-2 residues at the C terminal domain (CTD) of RNAPII as well as DSIF/Spt5. While our work revealed that phosphatases are recruited co-transcriptionally in mammalian cells to promote pausing, it remains unknown how Int-PP2A’s activity is established at the proximal promoter and how it is modulated. Here we propose to: a) determine how Int-PP2A establishes paused RNAPII via the INTS3 subunit; b) determine the role of PP2A carboxy-methylation in transcriptional regulation; c) determine the effect of mutant PP2A on transcription in models of neuronal differentiation. Project Number: 1R01GM152664-01A1 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of General Medical Sciences (NIGMS) | Principal Investigator: Alessandro Gardini | Institution: WISTAR INSTITUTE, PHILADELPHIA, PA | Award Amount: $591,549 | Activity Code: R01 | Study Section: Cellular Signaling and Regulatory Systems Study Section[CSRS] View on NIH RePORTER: https://reporter.nih.gov/project-details/11376134